The Succubus is a pretty easy boss if you know what to do. She will crawl up to which ever platform you are on and swipe at you with one of her many hands. Evade any swipe attempt, then attack the other hands that are on the platform. If you have the Demon Evade, you can do this and gain some power at the same time.

Every now and then Succubus' weak spot will show. The weak spot is this red ball above her face. If you see it, jump in the air and attack it, or use a launch type attack that can reach it.

After a few attacks, the Succubus will cover the platform in acid. Jump to the left or right and use the Angel Lift ability to reach another platform. Keep doing the same attacks as mentioned earlier until she falls.

When she falls, four tubes will become exposed. Use the Demon Pull ability to rip them out of their sockets. Once the Succubus recovers, run to any other platform you can, chances are she will smash the platform you're currently on.

Keep doing the same attacks and pulling out the plugs until there are none left. All that will be left to do is completely empty her health bar and do one final demon pull.

The next thing to do is run to the exit. Use the Angel Lift when you see the blue hook above. A short cut scene will play.

The final "attacks" are series of Angel Lifts and Demon Pulls. When the Succubus is hanging on for dear life, cut her hands with any blade you like.